Inkjet printers typically utilize a printhead that includes an array of orifices (also called nozzles) through which ink is ejected on to paper or other print media. One or more printheads may be mounted on a movable carriage that traverses back and forth across the width of the paper feeding through the printer, or the printhead(s) may remain stationary during printing operations, as in a page width array of printheads. A printhead may be an integral part of an ink cartridge or part of a discrete assembly to which ink is supplied from a separate, often detachable ink container. For printhead assemblies that utilize detachable ink containers, it is important that the operative fluid connection between the outlet of the ink container and the inlet to the printhead assembly, commonly referred to as a fluid interconnection or “F.I.”, provide reliable ink flow from the container to the printhead assembly. Typically, ink is drawn from the ink container through a filter on the inlet to the printhead assembly. The inlet to the printhead assembly is commonly referred to as an inlet “tower” because it usually extends out from the surrounding structure. Excessive water vapor leaking from the ink container or printhead assembly at the F.I. could compromise critical properties of the ink. Thus, it is desirable to seal the FI against exposure to the atmosphere even after repeated installations and removals of the ink containers.
A rubber seal fitted around the outside of the tower, for example, may be used to help seal the FI. When an ink container is installed in the printhead assembly, the latching force used to secure the container in place in the printhead assembly presses the container outlet into the seal and compresses the seal against the base of the tower. When the container is removed, the seal rebounds back along the tower toward the original, uncompressed position. Thus, the rubber seal should fit closely to the tower but still be able to move up and down on the tower within a reasonable range of compression and rebound forces that may be generated in the seal with the container latching force. A rubber seal that moves up and down on a molded plastic boss, such as the F.I. tower structure, may employ a cylindrical inside surface mated with a cylindrical outside surface of the boss. The range of the normal force between the inside surface of the seal and the outside surface of the tower may vary by a factor of three depending on the dimensional variation of the parts within the manufacturing tolerance. This range of normal force and the resulting friction force, however, may impede the free movement of the seal on the tower, reducing the ability of the seal to rebound and reseal.